CARTILAGE MUCO OS TISSUE. 



75 



such a case occurs, the cartilage, which up to that time 

 had remained hyaline and homogeneous, becomes hete- 

 rogeneous and striated, and has long since been called 

 fibro-cartilage. 



From these forms a third has been distinguished, the 

 so-called reticular [yellow or spongy] cartilage, as seen 

 in the ear and nose, in which the cells are round, but 

 encircled by a peculiar kind of thick, stiff fibres, whose 

 mode of production has not yet been thoroughly made 

 out, but they are, perhaps, derived from the metamor- 

 phosis of the intercellular substance. 



Under these different types, presented by cartilage in 

 its different localities, all the different aspects which the 

 other connective tissues offer are included. There is 

 also true connective tissue with round, long, and stellate 

 cells. Just in the same manner we find, for example, 

 in the peculiar tissue which I have named mucous tissue 

 (Schleimgewebe), round cells in a hyaline, or spindle- 

 shaped ones in a striated, or reticular ones in a meshy, 

 basis-substance. The only criterion we possess for dis- 

 tinguishing them consists in the determination of the 

 chemical constitution of the intercellular substance. 

 Every tissue is called connective tissue whose basis- \ 

 substance yields gelatine when boiled ; the intercellular 

 substance of cartilage produces chondrine ; mucous tis- 

 sue, on expression, a substance, mucin, precipitable by 

 acetic acid, and insoluble in an excess of it, though dis- 

 solving in muriatic acid when added in considerable 

 quantity. 



Besides these, a few solitary points of difference in 

 regard to peculiarity of form and contents may be pre- 

 sented by individual cells at some later period of their 

 existence. What we concisely designate fat is a tissue 

 which is intimately connected with those of which we 

 have been treating, and is distinguished from the rest by 



